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Removing Old Registry Entries for Hardware That Does Not Appear in the Windows 2000 Device Manager

Hardware: Legacy DAQ Devices, Modular Instruments>>Digital Multimeters (DMM), Reconfigurable I/O (RIO), Modular Instruments>>Dynamic Signal Acquisition and Analysis (DSA), Modular Instruments>>High-Speed Digitizers (Scopes), Modular Instruments>>RF Measurement Devices, Modular Instruments>>High-Precision DAQ (Dataloggers), Counter/Timers (TIO), Digital I/O (DIO), Motion Control, GPIB, Signal Sources (AWG/FG/AO), Image Acquisition (IMAQ), Multifunction DAQ (MIO)

Problem:
Device Manager displays only non-Plug and Play devices, drivers, and printers when you click the Show hidden devices command on the View menu to enable it. Devices that are installed but are not currently connected to the computer, such as a Universal Serial Bus (USB) device or "ghosted" device, are not displayed in Device Manager, even when you use the Show hidden devices command.

Sometimes a registry entry related to a specific piece of hardware that is no longer in the computer may complicate the uninstallation or the upgrade of the driver for that hardware. Below is the procedure to clean up those registry entries.

Solution:
To work around this behavior and display all installed devices in the registry when you use the Show hidden devices command:

  1. Click Start, point to Programs, point to Accessories, and then click Command Prompt.

  2. At the command prompt, type the following lines, pressing ENTER after each line

    set devmgr_show_nonpresent_devices=1
    cd\%SystemRoot%\System32     (this line would normally be cd C:\WINNT\System32)
    start devmgmt.msc

    where %SystemRoot% is the folder in which Windows 2000 is installed.

  3. Troubleshoot the devices and drivers in Device Manager, as required.

    NOTE: You must first select show hidden devices from the Device Manager "View" menu before you can see devices that are no longer present in the system.

  4. When you are done troubleshooting, quit Device Manager, and then close the Command Prompt window.

NOTE: When you quit Device Manager and close the Command Prompt window, the set devmgr_show_nonpresent_devices=1 variable is turned off so you cannot see the phantom devices.

An alternative approach, for those who need this feature enabled constantly, is to set this environment variable globally. To do so, perform the following steps:
  1. Right-click My Computer.

  2. Click Properties.

  3. Click the Advanced tab.

  4. Click on the Environment Variables button.

  5. Add a new variable to the System Variables box.  The variable name should be devmgr_show_nonpresent_devices and the variable value should be 1.


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Report Date: 11/19/2002
Last Updated: 07/23/2008
Document ID: 2RIBR845

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